WASHINGTON — As the only Washington Redskins player born and bred in the nation’s capital, Joshua Morgan went up against the Dallas Cowboys many times in his imagination long before he did so in the NFL.

“I was either Art Monk beating the Cowboys,” Morgan said. “Or it was Jerry Rice in the Super Bowl.”

Redskins fans will forgive the Rice fantasy for now. The part about beating the Cowboys? It’s rarely been more urgent than right now.

The NFC East rivals have met 105 times over 52 years. Some have been classics. Some have been duds. Twice they’ve met in the NFC championship game. Eight times they’ve met to end the regular season, including a 1961 Washington victory that kept the Redskins from going winless and the last NFL game at RFK Stadium in 1996.

Only once have they met in the final week with playoff implications for both teams. Dallas beat Washington 35-34 on Dec. 16, 1979, rallying from 13 points down in the fourth quarter with two touchdown passes from Roger Staubach. The Cowboys finished 11-5 and won the NFC East. The Redskins dropped to 10-6 and stayed home.

Neither Morgan nor anyone else on either roster was alive for that game, so Sunday will be a new experience for all when the Redskins (9-6) and Cowboys (8-7) play winner-take-all for the division crown.

“You have to get up for this game more than any other game,” Redskins Pro Bowl left tackle Trent Williams said. “We’ve had to get up for all of them, but I think this one has a little special place.”

The Cowboys have to win to return to the postseason for the first time since 2009. The Redskins, absent from the playoffs since 2007, could lose and still get a wild-card berth, but only if both the Chicago Bears and Minnesota Vikings lose earlier in the day.

The NFL, knowing a good finish when it sees it, flexed the game to primetime, making it the 256th and final entry in the 2012 regular season schedule.

Even if this weren’t a rivalry, it would have the makings of high-ratings drama. The Redskins were once 3-6, the Cowboys 3-5. Washington is riding a six-game winning streak; Dallas is on a 5-2 run, with the only losses against the Redskins on Thanksgiving Day and in overtime last week against the New Orleans Saints.

Washington’s Robert Griffin III is setting new standards for rookie quarterbacks with his talent, leadership and star power. Unless he has a bad day, he’ll break the single-season NFL record for rookie passer rating, set by Ben Roethlisberger in 2004.

Even though he’s from Texas and went to college at Baylor, Griffin didn’t grow up with a dispassionate view of Cowboys-Redskins love-hate. Instead, he was a Denver Broncos fan.

“For guys like myself (and) the other rookies, we’re fresh into this rivalry,” Griffin said. “But we can definitely sense how the fans feel, how some of the guys who have been here for many years feel about the Cowboys, and that’s the mindset we have to take on. We’re doing it for them. We’re doing it for the fans.”

Tony Romo has set the Dallas record for yards passing and might hit 5,000 for the season, but, like the Cowboys in general in recent years, has been dogged by the inability to win consistently after Christmas. Romo has only one playoff win to his credit, and the franchise still stings from Week 17 playoffs-or-bust blowout road losses to the Philadelphia Eagles in 2008 and the New York Giants last year.

“Experience can be a really positive thing. It doesn’t always have to be a good experience. Sometimes it can be a bad experience,” Dallas coach Jason Garrett said. “When you didn’t get the job done, hopefully you can learn from what happened.”

But, for the most part, Cowboys players this week were careful not to dwell on those past failures, noting that every year’s team is different from those that played before. It took linebacker Brady Poppinga — a midseason pickup who has started one game — to seize the issue and offer it as a rallying cry.

“This place is becoming accustomed to these types of games,” Poppinga said. “Because I understand last year was essentially the same scenario, but instead of playing the Washington Redskins going to Washington they were playing the New York Giants.

“I think this place is due. For crying out loud, let’s get us one. What do you guys say? Is that a good idea? That’s what I think.”